This study looks at the audiological manifestations of this severe life-threatening autosomal recessive disorder. It is the purpose of this study to develop an audiologic profile for sclerosteosis as an aid in early diagnosis and as a tool for non-invasive monitoring of the progress of the disease. Patients and first degree relatives are being evaluated audiologically to determine the presence of significant electrophysiologic anomalies of the auditory system. For this group of patients, middle ear analysis includes otoadmittance measurements, a more detailed analysis of the function of the middle ear and one which is used in the NIH Audiology Clinic for all studies involving connective tissue disorder. Preliminary data to be presented in November, 1984, at the annual meeting of the American Speech, Language and Hearing Association.